> ## Documentation Index
> Fetch the complete documentation index at: https://docs.vambe.me/llms.txt
> Use this file to discover all available pages before exploring further.

# Send a free-form WhatsApp session message

> Sends a free-form text message inside an active WhatsApp conversation (the 24h customer-care window), without using a template. Target the recipient with "contact_id" or "phone". Only official WhatsApp API numbers are supported; WhatsApp rejects messages sent outside the 24h window.



## OpenAPI

````yaml /openapi.json post /api/public/whatsapp/message/session
openapi: 3.0.0
info:
  title: Vambe AI API
  description: Vambe AI documentation
  version: '1.0'
  contact: {}
servers:
  - url: https://api.vambe.me
    description: Production Server
security: []
tags:
  - name: Vambe AI
    description: ''
paths:
  /api/public/whatsapp/message/session:
    post:
      tags:
        - WhatsApp Message
      summary: Send a free-form WhatsApp session message
      description: >-
        Sends a free-form text message inside an active WhatsApp conversation
        (the 24h customer-care window), without using a template. Target the
        recipient with "contact_id" or "phone". Only official WhatsApp API
        numbers are supported; WhatsApp rejects messages sent outside the 24h
        window.
      operationId: PublicWhatsAppMessageController_sendWhatsAppSessionMessage
      parameters:
        - name: x-api-key
          in: header
          description: API key needed to authorize the request
          required: true
          schema:
            type: string
      requestBody:
        required: true
        description: The session message payload
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/SendSessionMessageDto'
      responses:
        '201':
          description: Message accepted for delivery.
        '400':
          description: Bad request.
        '401':
          description: Unauthorized.
        '404':
          description: No contact found for the given phone or contact_id.
components:
  schemas:
    SendSessionMessageDto:
      type: object
      properties:
        message:
          description: Free-form text body to send inside the active 24h session
          type: string
          minLength: 1
        contact_id:
          description: Vambe contact id to send the message to
          type: string
          format: uuid
          pattern: >-
            ^([0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[1-8][0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}|00000000-0000-0000-0000-000000000000|ffffffff-ffff-ffff-ffff-ffffffffffff)$
        phone:
          description: >-
            Recipient phone number, used when contact_id is not provided. Keep
            an explicit "+" for numbers in a different country than the sender
          type: string
        reply_message_id:
          description: Provider message id to quote when replying
          type: string
        from_phone_number:
          description: >-
            Business WhatsApp number to send from. Required when targeting by
            "phone" and the account has more than one WhatsApp number
          type: string
        type:
          description: Message type. Only "text" is supported for now
          default: text
          type: string
          enum:
            - text
        pause_assistant:
          description: Pause the AI assistant for this contact (human handoff)
          default: true
          type: boolean
      required:
        - message

````